Progressive addition lens design

Abstract

Aspects of the present invention provide progressive addition lenses (PALs) and techniques for designing PALs that result in improved visual performance for the wearer. PALs of the present invention can have vision zones with widths that are more in line with the actual or functional sizes used by wearers. PALs of the present invention can also introduce controlled amounts of unwanted astigmatism into one or more vision zones. By allowing vision zones to include manageable levels of astigmatism, the resulting PAL can avoid the harsh build-up of astigmatism typically found in conventional PALs at the periphery of the channel and viewing zones. Further, PALs of the present invention can be designed using a merit function to achieve an optimized iterative design that accounts for astigmatism vector orientation and not simply astigmatism magnitude as is the case with conventional PAL design.

What is claimed is: 
     
       1. An ophthalmic lens, comprising:
 a progressive optical power region having a channel, the progressive optical power region providing a far distance vision zone, an intermediate distance vision zone and a near distance vision zone, 
 wherein the channel length is 17 mm or less, 
 wherein the near distance vision zone provides at least 2.00 D of add power, 
 wherein the near distance vision zone comprises 0.50 D or less of unwanted astigmatism across the entirety of all portions of its width, and 
 wherein the far distance vision zone comprises 0.18 D or less of unwanted astigmatism. 
 
     
     
       2. The ophthalmic lens of  claim 1 , wherein the intermediate distance vision zone comprises 0.35 D or less of unwanted astigmatism. 
     
     
       3. The ophthalmic lens of  claim 1 , wherein the width of the near distance vision zone is 20 mm or less. 
     
     
       4. The ophthalmic lens of  claim 1 , wherein a width of the intermediate distance vision zone is 20 mm or less. 
     
     
       5. The ophthalmic lens of  claim 1 , wherein a width of the far distance vision zone is 40 mm or less. 
     
     
       6. The ophthalmic lens of  claim 1 , wherein the ophthalmic lens is a single layer lens having a front surface and a back surface. 
     
     
       7. The ophthalmic lens of  claim 1 , wherein the ophthalmic lens comprises two or more layers having one or more buried surfaces. 
     
     
       8. The ophthalmic lens of  claim 1 , wherein a maximum gradient of astigmatism at a periphery of the near distance vision zone is between 0.10 D/degree and 0.05 D/degree. 
     
     
       9. The ophthalmic lens of  claim 1 , wherein a maximum gradient of astigmatism at a periphery of the intermediate distance vision zone is between 0.20 D/degree and 0.05 D/degree. 
     
     
       10. The ophthalmic lens of  claim 1 , wherein a maximum gradient of astigmatism at a periphery of the far distance vision zone is between 0.15 D/degree and 0.025 D/degree. 
     
     
       11. The ophthalmic lens of  claim 1 , wherein the width of the near distance vision zone is 20 mm. 
     
     
       12. An ophthalmic lens, comprising:
 a progressive optical power region having a channel, the progressive optical power region providing a far distance vision zone, an intermediate distance vision zone and a near distance vision zone, 
 wherein the channel length is 17 mm or less, 
 wherein the near distance vision zone provides at least 2.00 D of add power, 
 wherein the near distance vision zone comprises 0.50 D or less of unwanted astigmatism across the entirety of all portions of its width, 
 wherein the width of the near distance vision zone is 14 mm, and 
 wherein the far distance vision zone comprises 0.18 D or less of unwanted astigmatism. 
 
     
     
       13. The ophthalmic lens of  claim 12 , wherein the ophthalmic lens is a single layer lens having a front surface and a back surface. 
     
     
       14. The ophthalmic lens of  claim 12 , wherein the ophthalmic lens comprises two or more layers having one or more buried surfaces. 
     
     
       15. An ophthalmic lens, comprising:
 a progressive optical power region having a channel, the progressive optical power region providing a far distance vision zone, an intermediate distance vision zone and a near distance vision zone, 
 wherein the channel length is 17 mm or less, 
 wherein the near distance vision zone provides at least 2.00 D of add power, 
 wherein the near distance vision zone comprises 0.50 D or less of unwanted astigmatism across the entirety of all portions of its width, 
 wherein the width of the near distance vision zone is 14 mm or less, and 
 wherein the far distance vision zone comprises 0.18 D or less of unwanted astigmatism. 
 
     
     
       16. The ophthalmic lens of  claim 15 , wherein the ophthalmic lens is a single layer lens having a front surface and a back surface. 
     
     
       17. The ophthalmic lens of  claim 15 , wherein the ophthalmic lens comprises two or more layers having one or more buried surfaces.